Lumbar spondylolysis repair rod

Abstract

A lumbar spondylolysis repair rod comprises a cylindrical rod body extending in the Z direction and having a diameter of 5.5 to 6 mm, wherein the lower end of the cylindrical rod body is provided with a transverse extension portion extending in the Y direction, a lamina hook is provided on one side of the transverse extension portion, a hook head of the lamina hook extends obliquely upward, an angle α formed between an extension line of the hook head and a straight line parallel to the cylindrical rod body in the Y direction is 30 to 60°, and an angle β formed between an extension line of the hook head and a straight line parallel to the cylindrical rod body in the X direction is 15 to 60°, and an opening width Q formed between the hook head and the transverse extension portion is 6 to 10 mm, thereby constituting a lumbar spondylolysis repair rod that conforms to the physiological and anatomical structure of the lumbar lamina and is integrated with the cylindrical rod body, the transverse extension portion and the lamina hook.

Description

Technical Field

[0001] The invention relates to a bone damage repairing device, in particular to a lumbar spondylolysis repairing rod. Background Art

[0002] In epidemiology, lumbar spondylolysis refers to the discontinuity of bone defects in the isthmus between the upper and lower articular processes of the lumbar vertebrae on one or both sides, also known as spondylolysis or isthmic nonunion. Most lumbar spondylolysis occurs in children and adolescents, and is one of the main causes of lower back pain in children and adolescents. Studies have shown that the incidence of spondylolysis in children before the age of 6 is 4.4%. Lumbar spondylolysis often occurs in L5 and L4, and is more likely to occur in certain athletes such as badminton players and weightlifters. Once lumbar spondylolysis occurs, the isthmus can hardly heal naturally due to local shear force.

[0003] Although most patients with simple lumbar spondylolysis can achieve good clinical efficacy and even bone healing through conservative treatment, some patients still have poor results from conservative treatment and persistent lower back pain, which seriously affects their daily life. In addition, 40-66% of patients with bilateral spondylolysis eventually develop lumbar spondylolisthesis, leading to lower limb nerve damage.

[0004] For patients who do not respond well to conservative treatment or have lumbar spondylolisthesis, surgical treatment is necessary. The current lumbar isthmus repair segmental fixation can directly repair the broken isthmus and fix it within the segment, which has little impact on the adjacent segments. Compared with lumbar fusion surgery, it is less traumatic and is a non-fusion surgery for lumbar function reconstruction. Its main methods include the following:

[0005] One is to use the Buck method of isthmic screw fixation technology, which directly passes the tension screw through the vertebral plate through the isthmic fracture and then fixes it. The operation directly restores the continuity of the isthmus, can pressurize the isthmus, meets the biomechanical requirements, and is conducive to isthmic bone graft fusion. Studies have shown that the fusion rate of lumbar isthmic spondylolysis is 83.5%, and the surgical complication rate is 13.4%. However, because the screw body occupies the isthmic bone graft space, it also affects the efficiency of bone graft fusion, which is difficult to implement in some patients with small isthmus development.

[0006] The other is the Scott method of transverse process-spinous process wire fixation technology and the modified Scott method fixation technology. This technology uses wire to fix the spinous process and bilateral transverse processes, and the modified method is to fix the spinous process and bilateral pedicle screws to achieve the purpose of pressure and fixation. Scott method of transverse process-spinous process wire fixation technology and modified Soctt method fixation technology, the wire used for fixation needs to be wrapped around the spinous process and pass through the yellow ligament, there is a risk of nerve damage, and the strength of the wire itself is relatively weak, so the fixation stability is poor, affecting the efficiency of isthmic bone graft fusion. Studies have shown that the fusion rate of lumbar spondylolysis is 81.6%, and the surgical complication rate is 22.4%.

[0007] Another method is pedicle screw-laminar hook fixation. After bone grafting at the isthmus fracture, a pedicle screw is placed above the isthmus fracture, and a lamina hook is installed below the isthmus fracture. Then, a connecting rod is used to connect and fix the pedicle screw and lamina hook, and pressure is applied to the fracture to achieve stability. With the continuous development of pedicle screw technology, pedicle screw-laminar hook technology ( Figure 4 ) is a relatively mature and widely used segmental fixation method for the treatment of lumbar spondylolysis. Since pedicle screws and lamina hooks can provide high stability, this technology has the characteristics of a high fusion rate. Studies have shown that the fusion rate of pedicle screw-lamina hook technology in the treatment of lumbar spondylolysis is 90.2%, and the surgical complication rate is 12.8%. Although the pedicle screw-laminar hook technique for the treatment of lumbar spondylolysis is one of the current mainstream surgical methods, it still has some shortcomings. The reasons are: first, the development of the spinal lamina varies from person to person, such as the thickness, width, and angle of the lamina with the spinous process, and the pedicle screw-laminar hook fixation products currently available on the market cannot meet individual requirements; second, when the connecting rod of the current technology connects the pedicle screw and the laminar hook, its placement position just corresponds to the isthmus bone grafting site. Since the bone grafting space in the isthmus is narrow and limited, the space occupied by the connecting rod will seriously affect the amount of bone grafting; and since the lamina and the spinal axis form an angle structure, and the existing laminar hook needs to be provided with a connecting head, an open groove for the connecting rod to be inserted and an internal threaded hole for the locking screw to be fixed are provided on the connecting head, resulting in a relatively large space occupied by the connecting head, and both ends of the connecting rod need to be fixed with the pedicle screw and the laminar hook respectively with screws, making it inconvenient to place and fix the pedicle screw-laminar hook fixation, resulting in a long operation time, increased bleeding, and increased complication rate. Summary of the invention

[0008] The purpose of the present invention is to provide a lumbar spondylolysis repair rod in view of the deficiencies in the prior art. The rod has a three-dimensional structure formed by a cylindrical rod body, a transverse extension portion, and a vertebral lamina hook, which is more in line with the physiological and anatomical parameters of the lumbar vertebral lamina and between the lumbar vertebral lamina and the spine. It can not only improve the firmness of the fixation between the vertebral lamina hook and the vertebral lamina, but also improve the stability of the pressurization of the lumbar spondylolysis repair. It also occupies a relatively small space, so that there is a larger bone grafting space at the isthmus fracture.

[0009] The object of the present invention is achieved in this way: a lumbar spondylolysis repair rod comprises a cylindrical rod body with a diameter of 5.5 to 6 mm extending in the Z direction, the lower end of the cylindrical rod body is provided with a transverse extension portion extending in the Y direction, a lamina hook is arranged on one side of the transverse extension portion, the hook head of the lamina hook extends obliquely upward, the angle α formed between the extension line of the hook head and the straight line parallel to the cylindrical rod body in the Y direction is 30 to 60°, and the angle β formed between the extension line of the hook head and the straight line parallel to the cylindrical rod body in the X direction is 15 to 60°, and the opening width Q formed between the hook head and the transverse extension portion is 6 to 10 mm, thereby constituting a lumbar spondylolysis repair rod that conforms to the physiological and anatomical structure of the lumbar lamina and is integrated with the cylindrical rod body, the transverse extension portion, and the lamina hook.

[0010] The lamina hook is an L-shaped flat hook, the hook head length C of the L-shaped flat hook is 6-10 mm, and the hook head width K is 6-10 mm.

[0011] The upper end face of the transverse extension portion is perpendicular to the cylindrical rod body, and the lower end face is a first inclined plane. The thickness between the first inclined plane and the upper end face gradually decreases from the starting point to the extended end of the transverse extension portion to form an angle ε of 15 to 60°. One side of the transverse extension portion is a vertical plane, and the lower end edge of the vertical plane coincides with the straight edge on one side of the first inclined plane. The other side of the first inclined plane is a hypotenuse, and the width between the hypotenuse and the straight edge gradually decreases from the starting point to the extended end of the transverse extension portion to form an angle θ of 30 to 60°. The side of the transverse extension portion on which the lamina hook is arranged is a second inclined plane, and the lower end edge of the second inclined plane coincides with the hypotenuse of the first inclined plane, and the upper end edge coincides with the hypotenuse of the upper end face of the transverse extension portion, so that the angle δ formed between the second inclined plane and the first inclined plane is 120 to 150°. The lamina hook is arranged on the second inclined plane, and the extension line of the hook head of the lamina hook is parallel to the second inclined plane.

[0012] The extension length of the lateral extension portion is 15 to 25 mm.

[0013] The two ends of the cylindrical rod are straight sections, and the middle section is an arc-shaped curved section, which is bent toward the straight surface of the lateral extension portion to form an angle γ of 150-165° between the straight sections at the two ends.

[0014] By adopting the above scheme, a transverse extension portion extending in the Y direction is provided at the lower end of a cylindrical rod body with a diameter of 5.5 to 6 mm extending in the Z direction, and a vertebral lamina hook is provided on one side of the transverse extension portion. The hook head of the vertebral lamina hook extends obliquely upward, and the angle α formed between the extension line of the hook head and the straight line parallel to the cylindrical rod body in the Y direction is 30 to 60°, and the angle β formed between the extension line of the hook head and the straight line parallel to the cylindrical rod body in the X direction is 15 to 60°. The opening width Q formed between the hook head and the transverse extension portion is 6 to 10 mm, thereby forming a lumbar spondylolysis repair rod that conforms to the physiological and anatomical structure of the lumbar vertebral lamina and is integrated with the cylindrical rod body, the transverse extension portion, and the vertebral lamina hook. This three-dimensional spondylolysis repair rod conforms to the physiological anatomy of the lumbar vertebral lamina. Different models of spondylolysis repair rods can be made according to the physiological anatomy parameters of the lumbar vertebral lamina of different individuals to meet the physiological anatomy parameter structures of the lumbar vertebral lamina of different individuals, so that the lamina hook can be firmly fixed to the lamina, and a greater force can be applied during the repair and pressure, so as to promote faster and better healing of the isthmus fracture. In particular, the inclination angle of the hook head extension line enables the lamina hook to be connected to the pedicle screw through the cylindrical rod body, so that the fixed lumbar segment can restore the normal physiological lordosis angle of the lumbar spine, which is conducive to the healing of the isthmus and reduces the impact on the adjacent segments. In particular, the opening width Q formed between the hook head and the lateral extension portion is 6 to 10 mm, which can adapt to the physiological anatomy parameter structures of the lumbar lamina of different individuals.

[0015] The lamina hook is an L-shaped flat hook, the hook head length C of the L-shaped flat hook is 6-10 mm, and the hook head width K is 6-10 mm. It can not only improve the strength of the lamina hook, but also make the lamina hook conform to the lumbar lamina structure, firmly hook the lumbar lamina, and at the same time reduce the pressure of the lamina hook on the lumbar lamina when applying force, avoid damage to the lumbar lamina, and apply greater force during lumbar spondylolysis repair, thereby improving the effect of lumbar spondylolysis repair.

[0016] The upper end face of the transverse extension portion is perpendicular to the cylindrical rod body, and the lower end face is a first inclined face. The angle ε formed between the first inclined face and the upper end face is 15 to 60 degrees, so that the thickness of the transverse extension portion gradually decreases from the starting point to the extension end of the transverse extension portion; one side of the transverse extension portion is a vertical surface, the lower end edge of the vertical surface coincides with the straight edge on one side of the first inclined face, and the other side of the first inclined face is a hypotenuse, and the angle θ formed between the hypotenuse and the straight edge is 30 to 60 degrees, so that the width of the first inclined face gradually decreases from the starting point to the extension end of the transverse extension portion. The side of the transverse extension portion on which the lamina hook is arranged is a second inclined face, the lower end edge of the second inclined face coincides with the hypotenuse of the first inclined face, and the upper end edge coincides with the hypotenuse of the upper end face of the transverse extension portion, so that the angle δ formed between the second inclined face and the first inclined face is 120 to 150 degrees; the lamina hook is arranged on the second inclined face, and the extension line of the hook head of the lamina hook is parallel to the second inclined face. By adopting this structure, the accurate setting of the inclination angle of the lamina hook of lumbar spondylolysis repair rods of different specifications and models can be ensured.

[0017] The extension length of the transverse extension portion is 15 to 25 mm, which can adapt to the physiological and anatomical parameter structures of the lumbar spine of different individuals.

[0018] The two ends of the cylindrical rod are straight sections, and the middle section is an arc-shaped curved section, which is bent sideways toward the straight surface of the transverse extension portion, so that an angle γ of 150 to 165° is formed between the straight sections at the two ends. This structure can adapt to the axial structure of the spine, and is more in line with the physiological and anatomical parameters between the lumbar vertebral plate and the spine, so that the cylindrical rod can be located outside the isthmus fracture when connected to the pedicle screw, so that the isthmus fracture has more space for bone grafting, thereby improving the bone graft fusion rate.

[0019] Compared with the prior art, the present invention has a relatively smaller volume, is more convenient for repair and fixation, has a more firm and stable fixation, is more conducive to pressurized repair, and improves the bone graft fusion rate. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a structural schematic diagram of the present invention;

[0021] Figure 2 for Figure 1 A-direction view;

[0022] Figure 3 for Figure 2 B-direction view;

[0023] Figure 4 for Figure 2 C-direction view. DETAILED DESCRIPTION

[0024] See also Figures 1 to 4An embodiment of a lumbar spondylolysis repair rod comprises a cylindrical rod body 1 with a diameter of 5.5 to 6 mm extending in the Z direction, and a transverse extension portion 2 extending in the Y direction is provided at the lower end of the cylindrical rod body 1, and the extension length of the transverse extension portion 2 is 15 to 25 mm. A lamina hook 5 is provided on one side of the transverse extension portion 2, and the hook head of the lamina hook 5 extends obliquely upward, and the angle α formed between the extension line of the hook head and the straight line parallel to the cylindrical rod body in the Y direction is 30 to 60°, and the angle β formed between the extension line of the hook head and the straight line parallel to the cylindrical rod body in the X direction is 15 to 60°, and the opening width Q formed between the hook head and the transverse extension portion is 6 to 10 mm, thereby forming a lumbar spondylolysis repair rod that conforms to the physiological and anatomical structure of the lumbar lamina and is composed of a cylindrical rod body, a transverse extension portion, and a lamina hook as a whole.

[0025] In order to improve the intensity of the lamina hook, the lamina hook can be made to conform to the lumbar lamina structure, firmly hook the lumbar lamina, and simultaneously reduce the pressure of the lamina hook on the lumbar lamina when applying force, so as to avoid damaging the lumbar lamina, and apply a larger force when repairing lumbar spondylolysis, so as to improve the effect of repairing lumbar spondylolysis. It is preferred that the lamina hook 5 of the present embodiment adopts an L-shaped flat hook structure, and the hook head length C of the L-shaped flat hook is 6-10mm, and the hook head width K is 6-10mm. Of course, in order to conform to the lumbar lamina structure of different individuals, the length and width of the hook head are not limited to the above parameters, and other suitable parameters can also be adopted according to the patient's lumbar lamina.

[0026] In order to ensure that the inclination angle of the lamina hook is more accurate when making a lumbar spondylolysis repair rod, the upper end face of the transverse extension portion is perpendicular to the cylindrical rod body, the lower end face is a first inclined surface 3, and the thickness between the first inclined surface and the upper end face gradually decreases from the starting point to the extended end of the transverse extension portion to form an angle ε of 15 to 60°. One side of the transverse extension portion 2 is a vertical surface 2a, and the lower end edge of the vertical surface 2a coincides with the straight edge of one side of the first inclined surface 3. The other side of the first inclined surface 3 is a bevel 3a, and the bevel 3a coincides with the straight edge of one side of the first bevel 3. The angle θ formed by the width between the straight edges gradually narrowing from the starting point to the extended end of the transverse extension portion is 30-60°, the side of the transverse extension portion where the lamina hook is arranged is the second inclined surface 4, the lower end edge of the second inclined surface 4 coincides with the inclined edge 3a of the first inclined surface 3, and the upper end edge coincides with the inclined edge of the upper end surface of the transverse extension portion, so that the angle δ formed between the second inclined surface 4 and the first inclined surface 3 is 120-150°, the lamina hook 5 is arranged on the second inclined surface 4, and the extension line of the hook head of the lamina hook 5 is parallel to the second inclined surface 4. In this way, the inclination angle of the lamina hook of different models of lumbar spondylolysis repair rods can be accurately set.

[0027] The two ends of the cylindrical rod body 1 of this embodiment are straight sections, and the middle section is an arc-shaped curved section, which is bent sideways toward the flat surface 2a of the transverse extension portion, so that an angle γ of 150 to 165° is formed between the straight sections at the two ends. In this way, the cylindrical rod body 1 can adapt to the axial structure of the spine, and is more in line with the physiological and anatomical parameters between the lumbar vertebral plate and the spine, so that the cylindrical rod body can be located outside the isthmus fracture when connected to the pedicle screw, so that the isthmus fracture has more space for bone grafting, thereby improving the bone grafting fusion rate. Of course, it is not ruled out that the cylindrical rod body 1 adopts a straight column structure, but the straight column structure cylindrical rod body 1 is easy to block the local space at the isthmus fracture, which increases the difficulty of bone grafting.

[0028] The lumbar spondylolysis repair rod is arranged into two specifications, namely, a left-side lumbar spondylolysis repair rod and a right-side lumbar spondylolysis repair rod, according to the position of the fractured side of the lumbar spondylolysis. The bending direction of the cylindrical rod body 1, the extending direction of the lateral extension part 2, and the setting position of the lamina hook 5 of the left and right-side lumbar spondylolysis repair rods are opposite to each other, so as to adapt to the left-side lumbar spondylolysis repair or the bilateral lumbar spondylolysis repair.

[0029] The present invention adopts one-piece processing and forming. By setting the extension direction and angle of the hook head of the lamina hook 5, the opening width of the lamina hook, the length and width of the hook head, and the bending angle of the cylindrical rod body 1, various types of lumbar spondylolysis repair rods can be produced, thereby forming a lumbar spondylolysis repair rod that conforms to the physiological and anatomical structure of the lumbar lamina and the anatomical parameters of the angle between the lumbar lamina and the spine and is integrated with the cylindrical rod body 1, the lateral extension part 2, and the lamina hook 6.

[0030] When the lumbar spondylolysis repair rod of this structure is used for lumbar spondylolysis repair, a C-arm X-ray machine is used to locate the surgical segment before the operation. A posterior median incision is used, and the median or intermuscular approach is used to expose the bilateral pedicle needle entry points, the broken isthmus, and the bilateral vertebral plates; the pedicles at the upper end of the broken isthmus are implanted with pedicle screws according to technical requirements; the vertebral plate hook 5 of the lumbar spondylolysis repair rod that conforms to physiological anatomy is hooked on the lower edge of the broken isthmus lamina, so that the upper end of the cylindrical rod body 1 is stuck in the open groove on the pedicle screw, the vertebral body is pressurized, pulled and reset, and then the cylindrical rod body 1 and the pedicle screw are locked and fixed with a locking screw; then an appropriate amount of autologous bone particles are taken from the patient and implanted in the processed isthmus broken end and compacted. The spondylolysis repair rod of the present structure is used to repair spondylolysis. After the lamina hook 5 is placed in place, the spondylolysis repair rod and the pedicle screw are locked and fixed only once with a locking screw, which simplifies the repair and fixation process. In addition, since the structure of the spondylolysis repair rod conforms to the physiological and anatomical structure of the lumbar spine, it is quick and convenient to place, which can shorten the operation time, reduce the amount of bleeding, and reduce the incidence of complications.

Claims

1. A lumbar spondylolysis repair rod, characterized in that: The invention comprises a cylindrical rod body with a diameter of 5.5 to 6 mm extending in the Z direction, wherein the lower end of the cylindrical rod body is provided with a transverse extension portion extending in the Y direction, a lamina hook is provided on one side of the transverse extension portion, the hook head of the lamina hook extends obliquely upward, the angle α formed between the extension line of the hook head and the straight line parallel to the cylindrical rod body in the Y direction is 30 to 60°, and the angle β formed between the extension line of the hook head and the straight line parallel to the cylindrical rod body in the X direction is 15 to 60°, the opening width Q formed between the hook head and the transverse extension portion is 6 to 10 mm, the upper end face of the transverse extension portion is perpendicular to the cylindrical rod body, the lower end face is a first inclined surface, the thickness between the first inclined surface and the upper end face gradually decreases from the starting point to the extension end of the transverse extension portion to form an angle ε of 15 to 6 0°, one side of the transverse extension portion is a vertical plane, the lower end edge of the vertical plane coincides with the straight edge on one side of the first inclined plane, the other side edge of the first inclined plane is a hypotenuse, the width between the hypotenuse and the straight edge gradually decreases from the starting point to the extending end of the transverse extension portion to form an angle θ of 30 to 60°, one side of the transverse extension portion on which the lamina hook is arranged is a second inclined plane, the lower end edge of the second inclined plane coincides with the hypotenuse of the first inclined plane, and the upper end edge coincides with the hypotenuse of the upper end face of the transverse extension portion, so that the angle δ formed between the second inclined plane and the first inclined plane is 120 to 150°, the lamina hook is arranged on the second inclined plane, and the extension line of the hook head of the lamina hook is parallel to the second inclined plane, thereby constituting a lumbar spondylolysis repair rod that conforms to the physiological and anatomical structure of the lumbar lamina and is integrated with a cylindrical rod body, a transverse extension portion, and a lamina hook.

2. The lumbar spondylolysis repair rod according to claim 1, characterized in that: The lamina hook is an L-shaped flat hook, the hook head length C of the L-shaped flat hook is 6-10 mm, and the hook head width K is 6-10 mm.

3. The lumbar spondylolysis repair rod according to claim 1, characterized in that: The extension length of the lateral extension portion is 15 to 25 mm.

4. The lumbar spondylolysis repair rod according to claim 1, characterized in that: The two ends of the cylindrical rod are straight sections, and the middle section is an arc-shaped curved section, which is bent toward the straight surface of the lateral extension portion to form an angle γ of 150-165° between the straight sections at the two ends.

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